This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Pulmonary partial pressure of oxygen (pO2) and oxygen depletion rate (ODR) are two important functional parameters of lung. The dependence of hyperpolarized (HP) 3He T1 on local oxygen concentration provides the basis for high-resolution mapping of the regional distributions of pO2 and ODR in the lung. Although the oxygen-sensitive HP 3He MRI technique has been applied in human subjects and several animal species, reproducibility studies are rarely reported in the literature. This work presents a preliminary reproducibility study on a pig model. In this study, important scan parameters, such as measurement timing and flip angle, are optimized to minimize the noise-induced measurement uncertainty.